Back in June, pollsters handed House Republicans some bad news. Seniors were complaining bitterly about the soaring cost of medicine, and unless the GOP countered the Democrats' plan to add a drug benefit to Medicare, they could kiss their majority goodbye in November. So on June 28, Republicans pushed a bill through the House that would enable the elderly to buy private drug insurance. Such quick GOP action is now helping to blunt Democratic attacks, says pollster Glen Bolger, in races such as the one in New Mexico's first district. There, incumbent Representative Heather A. Wilson (R-N.M.) is fighting challenger John Kelly, a former U.S. attorney. Says Bolger: ''Republicans who have been aggressive on the issue have done well.''

George W. Bush has taken a bit longer to get the message. That has opened a big door for Al Gore. At the Democratic convention in Los Angeles, a reinvigorated Veep put his rival in the unfamiliar position of being on the defensive by offering details of his own prescription-drug plan. ''Gore has raised the stakes by demanding that Bush come up with specifics,'' says political analyst Stuart Rothenberg.

SWEETENER. Now, stung by polls showing that making drugs more affordable for seniors is one of the top campaign issues--and that voters trust Democrats more than Republicans on health care--Bush finally is fighting back. In late August, he bought ads saying that his Administration would provide affordable drugs to needy seniors--and promised to provide all the arcane details right after Labor Day.

As in some of the House races, a Republican prescription-drug plan could help blunt this potent Democratic weapon. GOP strategists argue that the mere fact of having a detailed package is as important as the Bush plan's fine print in helping to convince voters that he cares. Moreover, the Bush approach is expected to follow closely the House model, which would allow seniors to buy subsidized insurance to cover some of their drug costs and which has the advantage of some Democratic support. And Bush will call for additional Medicare reform instead of just pasting a drug benefit onto the existing program. ''Unless Bush misplays the issue, it's probably not going to be decisive,'' says Rothenberg.

But Democrats believe they can still win the drug-benefit fight, even if it becomes a war of numbing details. The main reason: Their plan would be far more generous. For a modest monthly premium, it would eventually pay half the cost of up to $5,000 worth of drugs a year and limit each person's total out-of-pocket costs to $4,000. The total price tag to taxpayers: $338 billion over 10 years, according to the latest Congressional Budget Office estimate. In contrast, the House GOP plan would cost $159 billion over 10 years, providing much less subsidy. Elderly Americans will see past the rhetoric, predicts Stuart H. Altman, a professor of health policy at Brandeis University who favors the Democratic approach. ''For Bush to say he has a better plan is pure politics,'' he says. ''People get sophisticated pretty quickly when it affects them.''

Bush was expected to sweeten the plan somewhat in a Sept. 5 speech in Pennsylvania. Indeed, drugmakers, who back the private-insurer approach, privately say more bucks are essential. But Bush is in a bind, since he's committed to a tax cut of $1.3 trillion to $1.7 trillion over 10 years and billions in new spending that already eat up the surplus. ''Gore can take him apart on this in the debates,'' says a Capitol Hill staffer. ''This could be a triple--or a home run.'' And Gore's team is betting that may be enough for him to win the whole ballgame.